/* Copyright (C) 2004 - 2006  db4objects Inc.  http://www.db4o.com

This file is part of the db4o open source object database.

db4o is free software; you can redistribute it and/or modify it under
the terms of version 2 of the GNU General Public License as published
by the Free Software Foundation and as clarified by db4objects' GPL 
interpretation policy, available at
http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
Suite 350, San Mateo, CA 94403, USA.

db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */
namespace Db4objects.Db4o.Internal
{
	/// <exclude></exclude>
	public class Null : Db4objects.Db4o.Internal.IX.IIndexable4
	{
		public static readonly Db4objects.Db4o.Internal.IX.IIndexable4 INSTANCE = new Db4objects.Db4o.Internal.Null
			();

		public virtual object ComparableObject(Db4objects.Db4o.Internal.Transaction trans
			, object indexEntry)
		{
			return null;
		}

		public virtual int CompareTo(object a_obj)
		{
			if (a_obj == null)
			{
				return 0;
			}
			return -1;
		}

		public virtual object Current()
		{
			return null;
		}

		public virtual bool IsEqual(object obj)
		{
			return obj == null;
		}

		public virtual bool IsGreater(object obj)
		{
			return false;
		}

		public virtual bool IsSmaller(object obj)
		{
			return false;
		}

		public virtual int LinkLength()
		{
			return 0;
		}

		public virtual Db4objects.Db4o.Internal.IComparable4 PrepareComparison(object obj
			)
		{
			return this;
		}

		public virtual object ReadIndexEntry(Db4objects.Db4o.Internal.Buffer a_reader)
		{
			return null;
		}

		public virtual void WriteIndexEntry(Db4objects.Db4o.Internal.Buffer a_writer, object
			 a_object)
		{
		}

		public virtual void DefragIndexEntry(Db4objects.Db4o.Internal.ReaderPair readers)
		{
		}
	}
}
